Barbecued food has long been prized for its savory, mouth-watering flavor-especially wood smoke flavored "pit" barbecue that is slow cooked at low temperature. Details of the pit process are described in U.S. Pat. No. 3,589,269, disclosing an automatic barbecue oven including a pyrolytic smoke forming surface that provides smoke to enhance the flavor and aroma of the food. Eating pit barbecue evokes memories of communal outdoor cooking over open fires while picnicking or camping thus adding to the enjoyment of the experience.
Consequently, there is an ongoing motivation in the art to move barbecue cooking indoors and to reduce cooking times (through use of higher temperatures). This motivation drives the ongoing re-design and development of electrically powered barbecue grills. Indoor, smokeless grills are common in the art; however, food cooked on smokeless grills has the appearance but lacks the aroma and flavor of outdoor barbecue. Smoke free, high temperature indoor barbecue cooking that more completely captures the essence of the pit barbecue process became possible with the advent of downdraft ranges and cooktops as described U.S. Pat. Nos. 3,444,805, 3,474,724, 3,745,912, 4,862,795, and 5,287,799.
The components in grill assemblies designed for use in downdraft ranges and cooktops are gravity drained and therefore vertically stacked. In such an arrangement, drippings, rendered from food during cooking, drain from a food rack positioned uppermost in the stack, through electric heating elements positioned beneath the food rack, and collect in a drip pan positioned beneath the heating elements. Radiant heat emitted from the bottom of the heating elements can heat grease collected in the drip pan to its flash point. The occurrence of flash fires, can be reduced by insertion of heat sink plates (as shown in U.S. Pat. No. 3,745,912) or reflector pans (as shown in U.S. Pat. No. 4,862,795) beneath the heating elements. Heat sink plates usually contain one or more through openings to expedite the rapid drainage of drippings through the plate into the drip pan. Furthermore, the upward facing surfaces of the plates are sloped to drain drippings toward the openings.
Heat sink plates also beneficially enhance production of savory, aerosols (smoke) within the barbecue by aiding violent boiling and spattering associated with the pyrolysis of food drippings as they flow over the hot surface of the plate enroute to the drip pan. The plate also provides a convenient repository for optional placement of various types of wood chips within the barbecue.
From the foregoing, it is easy to see that during use heat sink plates become covered with charred residues that plug the through openings and make heat sink plates difficult to thoroughly clean. The residues, which quickly become foul smelling, stick tenaciously to the heat sink plate and reduce heat flow to the surface of the plates thus impeding pyrolysis of drippings. Often prolonged soaking in warm detergent-water solution followed by vigorous scrubbing with steel wool, ScotchBrite.TM., or a brass bristle grill brush fails to completely remove the char.
Applicant is not aware of any flavor producing or heat sink plates designed for use beneath electric heating elements that have anti-stick coatings of Teflon.TM. applied thereto. However, the prior art does describe barbecue grills having Teflon.TM. coated components like food racks and drip bars that are located well away from heat sources. For example, U.S. Pat. No. 5,259,299 describes a non-stick outdoor cooking unit having Teflon.RTM. coated cooking surfaces. The unit is designed and constructed for continuous service at temperatures of 500 degrees Fahrenheit. The design precludes direct flame contact and overheating of the Teflon.RTM. coating. The patent further describes flu like symptoms (sometimes called "polymer fume fever") that have been reported by people breathing Teflon.RTM. decomposition products.